Suspension devices each include a spring, a damper (or a shock absorber), and a stabilizer bar. The suspension devices are devices that provide good ride quality and stability by performing three functions, for example, a function of adjusting a spring constant, a function of adjusting a damping force (or an attenuating force), and a function of adjusting a vehicle height level.
The damper includes a piston assembly that forms a circulation path for internally circulating oil filled therein upward and downward. The damper absorbs and buffers shock and vibration applied to a vehicle.
Recently, technology for connecting a suspension device to an electric power generating apparatus in addition to simply improving the ride quality and stability of a vehicle has been developed. As an example of the technology, an electric power apparatus using a suspension device is disclosed in Korean Patent Publication No. 2009-0128822 (hereinafter referred to as the prior art reference).
The prior art reference discloses a technical configuration where a damper configuring a suspension device is connected to an energy recovery device such as a turbine means through a tube, a piston provided in the damper performs a vertical motion, oil filled into the damper is moved into the energy recovery device through the tube, and the moved oil rotates wings of the turbine means to generate electric energy.
The energy recovery device disclosed in the prior art reference acts as an element that obstructs an original function of the suspension device.
In the prior art reference, since a difference occurs between an operation speed of the energy recovery device and an operation speed of the suspension device, shock cannot be smoothly absorbed on an under-construction road or an unpaved road from which a large bump is expected. That is, the energy recovery apparatus obstructs a shock absorbing operation that is an original function of the suspension device.
The stabilizer bar reduces a roll motion of a vehicle body. However, due to the energy recovery device, when the stabilizer bar is broken down or is late in convergence behavior, ride quality is degraded.